Field
This disclosure relates to a positive active material for a rechargeable lithium battery, a method of preparing the same, and a positive electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same.
Description of the Related Technology
Lithium rechargeable batteries have recently drawn attention as a power source for small portable electronic devices, and use an organic electrolyte. A lithium battery may have twice or more discharge voltage than a conventional battery using an alkaline aqueous solution, and accordingly have high energy density.
A rechargeable lithium battery may be manufactured by injecting an electrolyte into a battery cell, which includes a positive electrode including a positive active material capable of intercalating/deintercalating lithium ions and a negative electrode including a negative active material capable of intercalating/deintercalating lithium ions.
As for the positive active material, LiCoO2 has been widely used but has a limit for increase of energy density and output characteristics due to reversible capacity of less than or equal to 200 mAh/g. In particular, when the LiCoO2 is used in a high energy density-applying field, the LiCoO2 may be structurally unstable and deform during the charge.
However, an overlithiated layered oxide (OLO) including lithium as a composite of Li2MnO3 and Li(Ni/Co/Mn)O2 shows high charge and discharge capacity at a high voltage.
However, an OLO rarely is applied to a commercially available battery as a positive active material due to capacity deterioration and voltage drop, as charge and discharge are repeated.